DANVILLE — A tree fell on Mount Diablo State Park campers Friday night, injuring two people, according to firefighters.

The tree toppled over at the Live Oak Campground around 10:40 p.m. Friday. One camper was taken by ambulance to a hospital and another was airlifted, said San Ramon Valley Fire District Battalion Chief Dan McNamara. The extent of the unidentified campers’ injuries wasn’t confirmed by afternoon.

Two campsites remained closed, but the campground is open, said Bruce Erickson, who was working the South Gate kiosk Saturday.

It was unknown what caused the valley oak to topple. Remaining campers were offered a refund if they wanted to leave, but no one had left by noon Saturday, Erickson said.